CN112510735B

CN112510735B - Power dispatching system and power dispatching method

Info

Publication number: CN112510735B
Application number: CN202011015793.6A
Authority: CN
Inventors: 葛炽昌
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-09-24
Filing date: 2020-09-24
Publication date: 2023-06-20
Anticipated expiration: 2040-09-24
Also published as: CN112510735A; EP3974244A1; TW202213893A; US11962154B2; JP7210671B2; US20220094165A1; JP2022053514A; TWI786826B

Abstract

A power dispatching system and a power dispatching method. The power dispatching system is provided with a plurality of accommodating spaces, a direct current bus, an alternating current-direct current power supply conversion device and an energy control center. The exchange battery pack in each accommodating space is coupled to the direct current bus, and the alternating current-direct current power supply conversion device is coupled between the direct current bus and a power grid. The power dispatching method comprises the steps of intensively storing a plurality of exchange battery packs from different electric vehicles; and the energy control center controls the exchange battery packs to participate in a first power dispatching task to provide power dispatching for the power grid through the direct current bus and the alternating current-direct current power supply conversion device.

Description

Power dispatching system and power dispatching method

Technical Field

The present invention relates to a power system and an operating method thereof, and more particularly, to a power dispatching system and a power dispatching method thereof.

Background

The electric energy is the most dense, widely distributed and most used energy form in the world at present due to the convenient use. However, when the power load is higher than the generated energy or lower than the generated energy, the frequency of the power grid may change and may cause the breakdown of the power grid, so that the power system is required to be maintained stable, the supply and demand balance is required to be maintained at any moment, and the power supply is adjusted in time to adapt to the power load demand, namely the scheduling work. In recent years, green energy such as solar energy, photoelectricity, wind power and the like is used for generating electricity, and the generated power is difficult to master, so that not only is the cost increased for power dispatching work, but also the stability of a power grid is more difficult to maintain.

The inertia (inertia) of the green energy source is much smaller than that of the traditional generator set, and the frequency of the power generation system is easy to deviate from the target value when the normal power generation output fluctuates. When the system is subjected to accidental tripping, the total inertia of the system with higher proportion of green energy power generation is smaller, and the frequency response of the power generation system is faster, so that the problem of system stability is easier to cause, and the difficulty of power dispatching of a modern power grid is highlighted.

Generally, electric power is generally obtained by thermal power generation, hydroelectric power generation, or nuclear power generation. Among them, the basic power source is from nuclear power generation or thermal power generation, and when there is an unexpected urgent need, the hydraulic power generation is generally selected. Because the characteristic of hydroelectric generation is that the starting is fast, the power can be quickly connected in grid. However, the disadvantage of hydroelectric power generation is that the water after power generation cannot return again, and the water is pumped to the upper pool for storage at the time of low peak of electricity consumption, so that the limitation of natural factors such as limited construction environment, low efficiency, rainfall and the like is caused.

In order to solve the problem of insufficient peak or instant electric energy, the battery energy storage power generation is adopted to replace hydroelectric power generation or water pumping and storage capacity power generation in the industry, and the characteristic of quick response of the battery energy storage power generation is more an optimal scheduling scheme of low-inertia green energy power generation. However, the cost of energy storage and power generation of the battery is quite expensive, at least including the power grid power generation cost, the battery depreciation cost and the re-generation cost, the current average cost of the lithium battery for energy storage is about $180-200 per kilowatt hour, and compared with the power generation cost of other energy storage power plants, the lithium battery for energy storage is quite expensive. Therefore, the cost of the investment is considerable if a battery energy storage power plant is to be built separately.

Therefore, how to more economically and effectively schedule power according to the demands of the power grid to maintain the stability of the power system is one of the current important problems.

Disclosure of Invention

In view of the foregoing, an object of the present invention is to provide a power dispatching system and a power dispatching method, which can achieve flexible dispatching of power and reduce cost by executing three functions of peak load elimination of a power grid, energy storage and power generation of a battery, and battery exchange of an electric vehicle in a single power dispatching station.

In order to achieve the above object, the present invention provides a power scheduling method, which is applied to a power scheduling station. The power dispatching station is provided with a plurality of accommodating spaces for storing the exchange battery packs, a direct current bus and an alternating current-direct current power supply conversion device. Each accommodating space is provided with a corresponding connector which is coupled to the direct current bus, and the alternating current-direct current power supply conversion device is coupled between the direct current bus and a power grid. The power scheduling method at least comprises the following steps.

The first step is to store a plurality of exchange battery packs from electric vehicles of different specifications or models in the accommodating space in a concentrated manner, and each exchange battery pack is electrically connected with a corresponding connector of the corresponding accommodating space.

And secondly, controlling the alternating current-direct current power supply conversion device and the exchange battery packs positioned in the accommodating spaces by an energy control center, and assigning at least part of the exchange battery packs positioned in the accommodating spaces to participate in a first power dispatching task according to a first power demand instruction. The first power dispatching task comprises that the assigned part of the exchange battery pack discharges the direct current bus or is charged by the direct current bus, so that the exchange battery pack provides power to the power grid or consumes power of the power grid through the direct current bus and the alternating current-direct current power supply conversion device. And, at least one of the assigned switching battery packs was charged at another power dispatching station.

In one embodiment, during execution of the first power scheduling task, the portion of the switched battery pack not engaged in the first power scheduling task is charged via the dc bus.

In an embodiment, the energy control center further executes a second power scheduling task according to a second power demand instruction, and assigns a different number of switch battery packs than the first power scheduling task to participate in the second power scheduling task, or assigns a part of switch battery packs not participating in the first power scheduling task to participate in the second power scheduling task.

In one embodiment, the energy control center further performs a second power scheduling task according to a second power demand command. At least part of the exchange battery packs participating in the first power dispatching task and the second power dispatching task are located in different accommodating spaces.

In one embodiment, the number of switching battery packs participating in the first power scheduling task may be increased during the first power scheduling task.

In one embodiment, the first power scheduling task includes a first power scheduling task and a first power scheduling task. The first power generation and power dispatching task comprises discharging the direct current bus through the exchange battery pack, so that the exchange battery pack provides power for the power grid through the direct current bus and the alternating current-direct current power supply conversion device. The first electric power dispatching task comprises charging the exchange battery pack partially positioned in the accommodating space by the direct current bus, so that the exchange battery pack is charged by the direct current bus and the alternating current-direct current power supply conversion device, and then the electric network power is used.

In one embodiment, the first power generation scheduling task is such that the sum of the currents flowing through the switching battery pack to the dc bus is increased.

In one embodiment, the first power scheduling task is to increase the sum of the currents flowing through the dc bus to the switching battery pack.

In one embodiment, the energy control center controls the voltage of the dc bus to be within a predetermined range.

In one embodiment, the exchange battery pack partially participating in the first power dispatching task is charged and then loaded into an electric vehicle to charge a main battery pack of the electric vehicle.

In one embodiment, a swap battery pack that partially participates in a first power scheduling task has already participated in a power scheduling task of a different power scheduling station.

In an embodiment, during the process of executing the first power scheduling task, the exchange battery pack at least partially located in the accommodating space may be assigned to exit the charging task, while the exchange battery pack at least partially located in another portion of the accommodating space is assigned to participate in the power scheduling task.

In one embodiment, the energy control center further receives a second power demand command and performs a second power scheduling task. Wherein the second power demand instruction is the same as the first power demand instruction, however at least a portion of the swapped battery packs that participated in the second power scheduling task were not engaged in the first power scheduling task. Here, the "same power demand command" is, for example, a power generation amount in which the power grid needs the same power and the same time.

In addition, in order to achieve the above purpose, the present invention also provides a power dispatching system, which is used in cooperation with a power dispatching station. The power dispatching station stores a plurality of exchange battery packs from different electric vehicles in a centralized way. Each exchange battery set is provided with a direct current power converter which is coupled with each other and a plurality of battery units which are electrically connected with each other. And at least some of the exchange battery packs may have the same exterior shape and different capacity specifications. The power dispatching system comprises a plurality of accommodating spaces, an alternating current-direct current power supply conversion device and an energy control center. The corresponding connectors are respectively arranged in the accommodating spaces and are used for being connected with a corresponding exchange battery pack, and the connectors are also coupled with a direct current bus. The AC/DC power conversion device is coupled between the DC bus and a power grid. The energy control center controls the AC/DC power supply conversion device and the exchange battery packs positioned in the accommodation spaces to enable the exchange battery packs positioned in the accommodation spaces to participate in a first power dispatching task according to a first power demand instruction. Wherein the power scheduling tasks include power generation power scheduling tasks or power utilization power scheduling tasks. The power generation power dispatching task comprises discharging the direct current bus by the exchange battery pack, and enabling the exchange battery pack to provide power for a power grid through the direct current bus and the alternating current-direct current power supply conversion device. And, at least one of the assigned switching battery packs was charged at another power dispatching station.

In one embodiment, in the power dispatching system, during the execution of the first power dispatching task, the part of the exchange battery pack not participating in the first power dispatching task may start to be charged through the dc bus.

In one embodiment, the switching battery packs participating in the first power scheduling task have different capacity specifications. In one embodiment, the ac/dc power conversion device includes a plurality of power conversion units. The power conversion unit is selected from a direct current to alternating current conversion unit, an alternating current to direct current conversion unit and a combination thereof.

In one embodiment, the DC power converter in the switching battery pack is non-isolated.

In one embodiment, the dc power converter in the exchange battery pack is a bi-directional dc power converter.

In one embodiment, the ac/dc power conversion device is connected to the power grid through a transformer.

In one embodiment, the dc bus voltage is higher than the voltage of the battery pack inside the exchange battery pack.

In the invention, the exchange battery pack is separated from the electric vehicle and then is concentrated to the power dispatching station through the electric vehicle with the exchange battery pack and the main battery pack. The system comprises a power dispatching station, a power dispatching system, a power dispatching method and a power dispatching system, wherein the power dispatching station is used for executing three functions of battery exchange, peak load elimination of a power grid, a battery energy storage power generation system (Energy Storage System) and the like of the electric vehicle, the power dispatching is achieved by matching with the power dispatching method and the power dispatching system, and the hardware facilities of the power dispatching station and the battery exchange station are shared to integrate the battery exchange station and the battery energy storage power generation of the electric vehicle, and the efficiency of circulating operation, flexibly dispatching power and reducing cost is achieved by sharing management cost together. Hereinafter, the main technical features of the present invention will be briefly described.

The corresponding connectors are arranged in the accommodating spaces, namely, each accommodating space has a corresponding connection relation, and the connection relation is that the accommodating spaces are connected with the corresponding connectors, the coupled direct current buses, the coupled alternating current-direct current power supply conversion devices and then reach the power grid. The connection relation can be a fixed framework or an unfixed framework formed by components such as a relay, namely, the exchange battery pack is connected with the power grid through the connection relation.

The presentation regarding the use of a shared exchange battery pack as a battery exchange for an electric vehicle is: the exchange battery packs detached by the electric vehicles with different specifications or models are recharged in the same accommodating space of the different electric vehicles after being charged by the power dispatching station, and the main battery packs with different specifications or models in the different electric vehicles are charged. The same accommodating space of different electric vehicles does not represent that the sizes of the accommodating spaces on different electric vehicles are completely the same, but represents the exchange battery packs which are designed in accordance with the same appearance standard, so that compatibility among the battery packs is ensured, and the same accommodating space of different electric vehicles or the same accommodating space of the power dispatching station can be arranged.

Similarly, the same shape of the exchange battery pack does not represent the same size, but represents the same shape specification which must be met in design to ensure compatibility. In the example of compatibility, taking a fourth battery (AAA) of a dry battery as an example, the external dimensions of the same fourth dry battery of different brands are not identical, and the dimensions of the same accommodating space of different toys are not identical, because the design accords with the same external specification, the compatibility in use can not be caused.

The system for achieving peak load elimination of the power grid and battery energy storage and power generation by using the shared exchange battery pack in a centralized way is shown as follows: and unloading the exchange battery packs by electric vehicles with different specifications or models, and concentrating the exchange battery packs in the power dispatching station. In these removed exchange battery packs, which may have different capacities, the same accommodation space may be placed to connect to a dc bus for charging or for generating electricity to the grid. Battery exchanges must have a sufficient number of battery pack inventory, storage space, configuration specific handling devices, charging devices, and management facilities; the peak load of the power grid is eliminated, and the battery energy storage and power generation must have enough power generation capacity (battery pack stock), storage space, charging device, power generation device and management facility to update the real-time backup capacity at any time.

In the power dispatching, the electric vehicle with the exchange battery pack and the main battery pack freely moves among power dispatching stations between cities and highways, and the exchange battery pack is separated, concentrated and subjected to charge and discharge dispatching by the electric vehicle to achieve the purpose of power dispatching.

Where "assignment" is the requirement that multiple designated switching battery packs participate in a power scheduling task. Wherein the designation of connection relationships is also part of the assignment if they are non-fixed structures similar to those described above. For example, the first and second switching battery packs are connected to the dc bus via the first and second relays, respectively, and the first and second relays are open in a normal state, and the first relay must be assigned a short circuit state if the first switching battery pack participates in the power scheduling task.

The assignment also has a control meaning that represents the manner in which control is assigned to the selected switching battery pack. For example, when the required power is 10KW (10 KW), 10 sets of exchange battery packs may be selected, wherein 10 sets are all set to 1KW output, or 5 sets of 1.2KW and 5 sets of 0.8KW output may all represent the same output. For example, when the required power is 20KW, 20 sets of the exchange battery packs may be selected, wherein all of the 20 sets are set to an output of 1KW, or 10 sets of the exchange battery packs may be selected, and all of the 10 sets are set to an output of 2KW, which is also represented as the same output.

The power dispatching task includes a power dispatching task and a power dispatching task, and regarding the power dispatching task, the power dispatching task refers to that the power dispatching station executes increasing of the available electric quantity of the power grid (equivalently reducing the electric quantity of the power grid of the power dispatching station) according to the power demand instruction, and the method includes that the power dispatching station uses the electric quantity of the power grid for reducing (power grid peak elimination) or changes the power consumption into energy storage power generation or increases the energy storage power generation. In short, it means that the sum of the currents flowing to the dc bus for all the switching battery packs is increased.

With respect to electricity power dispatching tasks, it refers to that a power dispatching station performs increasing the usage amount of power of a power grid according to a power demand instruction, and the method includes reducing the energy storage power generation amount of the power dispatching station, changing the energy storage power generation into electricity (grid filling) or increasing the electricity consumption (grid filling). Wherein the electricity is mainly charged by a battery. In other words, it means that the sum of the currents flowing through the dc bus to all the switching battery packs is increased.

The exchange battery pack consists of battery units coupled with a direct current power converter, and different exchange battery packs can consist of battery units with different specifications. When the power dispatching station executes the power dispatching task, not only the power of the alternating current-direct current power supply conversion device is controlled, but also the direct current power supply converters of the exchange battery packs participating in the power dispatching task are also controlled simultaneously so as to ensure that the direct current bus is in a correct working range.

The design of the exchange battery pack is mainly matched with a main battery pack matched when leaving a factory, so that the electric vehicles of different brands can exert the inherent characteristics. The parameters such as the specification and the working mode of the direct current power converters of different exchange battery packs are different, and when the power dispatching task is executed, the control of each participating exchange battery pack is required.

When the number of electric vehicles becomes larger, the power dispatching station stores a larger number of exchange battery packs in order to cope with the need of exchanging the exchange battery packs of the electric vehicles. The power dispatching station has a larger capacity of the exchange battery pack than that of a general battery energy storage power plant. Assuming that the capacity of the exchange battery pack of one electric vehicle is 20KWh, when 10,000 electric vehicles move between cities, it means that the total capacity of the exchange battery packs is 200MWh. When there are a sufficient number of electric vehicles, the number and capacity of the exchange battery packs stored in the power dispatching station are considerable. In contrast to the largest battery energy storage power plant in the world in 2018, the battery capacity of the us Tesla company (Tesla) in australia Huo Ensi dale (Hornsdale) wind power plant is 129MWh, which is a knowledge of the huge battery capacity owned by the power dispatching station.

The battery capacity of a traditional battery energy storage power station is basically fixed, and no charging is needed after full charge and before the next power generation task. However, the power dispatching station needs to constantly supplement the exchange battery pack which needs to be charged when the electric vehicle is replaced, and the peak load shifting work of the power grid can be easily achieved due to the huge and frequent charging requirement and the huge battery capacity reserve caused by the flow of the electric vehicle.

The power demand command represents unbalanced supply and demand of the power grid, and accordingly, when the power dispatching task is a power dispatching task of power generation, the power dispatching station can selectively utilize the increase of the energy storage and the power generation capacity of the battery, or selectively reduce the total charge capacity of the exchange battery pack, or a combination thereof, so that the rated available electric quantity of the power grid is increased. When the power dispatching task is an electricity power dispatching task, the power dispatching station can select to utilize the battery to store energy, reduce the generated energy, or select to increase the total charge quantity of the exchange battery pack, or a combination of the total charge quantity and the exchange battery pack, so that the rated available electric quantity of the power grid is reduced.

In other words, after receiving the power demand instruction, the energy control center assigns at least part of the exchange battery packs located in the accommodating space to participate in the power dispatching task, and completes the power dispatching task and the power consumption dispatching task by controlling the increase or decrease of the total charge quantity, the increase or decrease of the total discharge quantity and the combination thereof of the exchange battery packs in the accommodating space.

In the above-mentioned manner, the power dispatching system and the power dispatching method of the present invention are to centralize the exchange battery packs for electric vehicles, and then adaptively dispatch the exchange battery packs for electric vehicles for use, so as to effectively integrate the increasingly used exchange battery packs for electric vehicles. The exchange battery pack can be provided for the electric vehicle after being charged, and can also be used for rapidly providing grid-connected power generation when the power grid needs standby power; when the power grid has redundant power, the total charge amount of the battery pack can be rapidly increased, so that the function of filling the valley of the power grid is achieved. The power dispatching system performs three functions of battery exchange, peak and valley elimination of a power grid and a battery energy storage and power generation system of the electric vehicle by intensively exchanging battery packs in a power dispatching station, and the shared exchanging battery packs, storage space, a charging device and management facilities can reduce fixed and variable costs.

Drawings

FIG. 1 is a schematic diagram of a battery configuration of an electric vehicle for use with the power dispatching system and dispatching method of the present invention;

FIG. 2 is a schematic diagram of a switch battery pack architecture for use with the power dispatching system and method of the present invention;

FIG. 3 is a schematic diagram of a power dispatching system according to a preferred embodiment of the present invention;

Fig. 4A and fig. 4B are schematic diagrams of connection structures of an ac/dc power conversion device and an exchange battery pack according to a preferred embodiment of the invention;

fig. 5A and fig. 5B are schematic diagrams of connection between a voltage-matched transformer and an ac/dc power conversion device and a power grid according to a preferred embodiment of the present invention;

FIG. 6 is a flow chart of the power dispatching system and method of the present invention for centralizing the exchange battery pack in the power dispatching station;

fig. 7 is a flowchart of a power scheduling method according to a preferred embodiment of the invention.

Description of the reference numerals

100: an electric vehicle; 101 a-101 d: a wheel; 11: a main battery pack; 12: exchanging the battery pack accommodating space; 13: exchanging the battery pack; 131: a DC power converter; 132: a battery unit; 133: a connection terminal; 20: a power dispatching system; 21: exchanging the battery pack; 21a1 to 21an, 21b1 to 21bn, 21z1 to 21zn, 21a 'to 21z': exchanging groups of cells; 211: a DC power converter; 212: a battery unit; 22: an accommodating space; 23: an AC/DC power supply conversion device; 231a to 231z: a power supply conversion unit; 24: an energy control center; 25: a direct current bus; 251a to 251z, 252a to 252z, 25na to 25nz: a sub-bus; 26. 261a-261z: a transformer; 27: an alternating current bus; 30: a power grid; i01: a first power demand instruction; S01-S04, S11-S18: and (3) step (c).

Detailed Description

In order that those skilled in the art will appreciate and realize the teachings of the present invention, reference will now be made to the appropriate embodiments and accompanying drawings in which like elements are provided with like reference numerals.

The terms "first," "second," and the like, as used herein, do not denote a particular order or sequence, but are not used to limit the invention, merely to distinguish one element or operation from another in the same technical term. In addition, "coupled" as used herein may include directly or indirectly electrically connected, or communicatively connected, data connected, etc.

Firstly, it is to be noted that the power dispatching system and the power dispatching method of the invention are matched with the electric vehicle and the exchange battery pack used by the electric vehicle. Referring to fig. 1, an electric vehicle 100 may include a main battery 11, an exchange battery accommodating space 12, and an exchange battery (swappable battery pack) 13.

The main battery 11 is disposed in a space between the four wheels 101 a-101 d of the electric vehicle 100 and is firmly combined with a vehicle body structure (not shown) of the electric vehicle 100, however, the actual configuration position of the main battery 11 may be changed according to the design of each vehicle type.

The exchange battery receiving space 12 can be loaded with and connected to exchange batteries 13 of different types or capacity specifications. The exchange battery accommodating space 12 is a semi-enclosed space or enclosed space (not shown) specially designed on the electric vehicle 100, and can stably accommodate the exchange battery 13 with a specific same shape. As shown in fig. 2, the exchange battery 13 has a direct current (DC-to-DC) converter 131, a plurality of battery cells (battery cells) 132 electrically connected to each other, and a connection terminal 133. The battery unit 132 may be a battery including, but not limited to, a lithium battery, a lithium cobalt battery, a lithium manganese battery, a lithium nickel cobalt battery, a lithium iron phosphate battery, and the like. The dc power converter 131 may be unidirectional or bidirectional, and may be independently designed according to the characteristics of the battery unit 132, so as to have a longer battery life and better power conversion efficiency. In addition, the dc power converter 131 is electrically connected to the connection terminal 133, and the exchange battery 13 is capable of transmitting power to the outside or receiving power transmitted from the outside through the connection terminal 133.

In the electric vehicle 100 described above, the outer shape of the main battery pack 11 is different from the outer shape of the exchanging battery pack 13, and the different exchanging battery packs 13 may have different capacity specifications. In other words, the same electric vehicle 100 can be loaded with different capacity of the exchange battery packs 13 at different time points, and the exchange battery packs 13 with different capacities can charge the main battery pack 11 or cooperate with the main battery pack 11 to provide the power required for running the electric vehicle 100. In addition, when the electric power of the electric vehicle 100 is insufficient, the battery may be selectively charged by the charging stake. However, even if the battery is charged by the fast charging device, it still takes at least 20 to 30 minutes, so that if the user is not in a long rest state, the user will choose to replace the battery pack 13 at a power dispatching station, so that the power source required by the electric vehicle 100 can be replenished in a short time (about 3 to 6 minutes), and the technology of using battery exchange in the long-distance travel on the expressway is a necessary means for replenishing the electric vehicle with electric power.

After the number of electric vehicles 100 and the number of points of the power dispatching stations are increased, a large number of exchange battery packs 13 flow between the electric vehicles 100 and the power dispatching stations with the movement of the electric vehicles 100 in the north-south direction. Further, the power dispatching station may not only provide the service of replacing the exchange battery pack 13 with the electric vehicle 100, but also charge the exchange battery pack 13 with insufficient power, or may utilize the exchange battery pack 13 to be connected to the power grid 30 and then serve as a power station, thereby filling the emergency of power shortage of the power grid.

Based on the above, referring to fig. 3 again, the power dispatching system 20 of the preferred embodiment of the invention includes a plurality of exchange battery packs 21, a plurality of accommodating spaces 22, an ac/dc power conversion device 23, an energy control center 24 and a dc bus 25. The power dispatching system 20 may be configured based on the point of the power dispatching station, which may be the point where the electric vehicle 100 replaces its exchange battery pack 21, and the power dispatching station also centrally stores a plurality of exchange battery packs 21 from different electric vehicles 100. Since these exchange battery packs 21 are circulated between the electric vehicle 100 and other power dispatching stations, it is one of the technical features of the present invention that the same exchange battery pack 21 performs power dispatching tasks at different power dispatching stations. Of course, the exchange battery pack 21 stored in the power dispatching station is not necessarily entirely from the electric vehicle.

The exchange battery pack 21 is accommodated in the corresponding accommodation space 22 and is stably accommodated therein. Similar to the aforementioned exchange battery pack 13, the exchange battery pack 21 has a dc power converter 211 and a plurality of battery cells 212 electrically connected to each other. In addition, a corresponding connector is disposed in each accommodating space 22 for connecting with the corresponding exchange battery pack 21, and the connector is further coupled to the dc bus 25. In the present embodiment, the exchange battery packs 21 concentrated on the power dispatching station have different capacity specifications, and these different capacity specifications of the exchange battery packs 21 may be randomly disposed in the corresponding accommodation spaces 22. In other embodiments, the exchange battery packs 21 with different capacity specifications may be classified and then concentrated in the corresponding accommodating spaces 22. Compared with the prior battery energy storage power station direct current bus connection, each string of batteries adopts the same specification, the battery unit 212 connected by the power dispatching station direct current bus 25 can adopt the exchange battery pack 21 consisting of battery units 212 with different specifications, which is one of the technical characteristics of the invention.

It should be noted that the accommodating space 22 is disposed at the power dispatching station, and a plurality of accommodating spaces 22 may form an exchange battery group 21a 1-21 an, 21b 1-21 bn, 21z 1-21 zn, 21a 'to 21z'. In addition, the exchange battery groups 21a 1-21 an, 21b 1-21 bn, 21z 1-21 zn, 21a 'to 21z' can be formed into a serial connection (connect in series), a parallel connection (connect in parallel) or a connection structure comprising serial and parallel connection at the same time by proper design.

The ac/dc power conversion device 23 is coupled between the dc bus 25 and a power grid 30. The ac/dc power conversion device 23 is used for converting dc power and ac power, and for example, discharges the exchange battery pack 21, transmits the discharge to the dc bus 25, converts the discharge to ac power, and transmits the converted ac power to the grid 30. The above-described manner of delivering ac power to the grid 30 may be referred to as grid-tied power generation. For example, the ac power of the power grid 30 is converted to dc power and transmitted to the dc bus 25 to charge the exchange battery pack 21.

The ac/dc power conversion device 23 may include a plurality of power conversion units 231a-231z (as shown in fig. 4A), which may include dc/ac conversion units, ac/dc conversion units, and combinations thereof. Here, the term "combination" means that a single power conversion unit has a function of converting dc to ac and vice versa. The front-end (forest) of the power conversion units 231a-231z may be directly electrically connected to the power grid 30 or connected to the power grid 30 through a

transformer

26, 261a-261z. The post-stage of the power conversion units 231a-231z is electrically connected to the exchange battery pack 21 in the accommodating space 22 through the connectors corresponding to the dc bus 25 and the accommodating space 22.

It should be noted that the dc bus 25 is a connection interface for connecting the ac/dc power conversion device 23 and the exchange battery pack 21 for power conversion. In the case of power dispatching, the power of the ac/dc power conversion device 23 is much larger than that of the dc power converter 211 of the switching battery pack 21, so that in general use, one ac/dc power conversion device 23 will be connected to a plurality of switching battery packs 21 via the dc bus 25. In the present embodiment, the dc bus 25 may further include a plurality of sub-buses 251a-251z, 252 a-252 z, 25 na-25 nz, which may be connected in a multi-stage serial connection manner, but is not limited thereto, and the purpose of the present invention is to obtain a higher output voltage after the dc bus 25 is connected in series, so as to connect to the ac/dc power conversion device 23 with higher power.

The energy control center 24 is electrically connected to the power grid 30, the ac/dc power conversion device 23, the dc bus 25 and the accommodating space 22, respectively, or performs control and information collection through data connection. The energy control center 24 is electrically connected to the receiving space 22 through a connector corresponding to the receiving space 22, so that communication can be established with the exchange battery pack 21 disposed in the receiving space 22. After the energy control center 24 establishes communication with the exchange battery pack 21, the energy control center 24 can obtain the electrical specification parameters and the real-time electrical parameters of the exchange battery pack 21, and can also control the working mode, the power supply capacity and the charging efficiency of the exchange battery pack 21.

The connection structure of the power dispatching system 20 between the ac/dc power converting device 23 and the exchange battery pack 21 can be varied, and only two embodiments of the connection structure are briefly described below with reference to fig. 4A and 4B, however, the topology of the circuit can be derived from the following two examples.

As shown in fig. 4A, in the first connection architecture, the ac/dc power conversion device 23 may include a plurality of power conversion units 231a-231z, which are respectively connected to the power grid 30, and each of the power conversion units 231a-231z is respectively connected to the corresponding exchange battery groups 21a 1-21 an, 21b 1-21 bn and 21z 1-21 zn through sub-buses 251a-251z, 252 a-252 z and 25 na-25 nz included in the dc bus 25, where the number of each exchange battery group is not required to be the same. The steady-state current of each power conversion unit 231a through 231z is equal to the sum of the steady-state currents of the parallel-connected exchange battery packs 21 connected in series, and since each exchange battery pack 21 has a dc power converter 211, each dc power converter 211 and the ac/dc power conversion device 23 must be controlled by the energy control center 24 to ensure that the dc bus 25 operates within a predetermined voltage range. This is why the above explanation is given to "assignment", which indicates the meaning of "assignment" in terms of the exchange battery pack 21, the connection relationship, and the control thereof, and the energy control center 24 can control and ensure the completion of the power dispatching task by the assignment. In addition, it should be noted that the symbols a, n, and z are merely symbols, and are not meant to represent quantities.

As shown in fig. 4B, in the second connection architecture, the power conversion units 231a-231z are connected in parallel between the power grid 30 and the sub-buses 251a-251z included in the dc bus 25, and the plurality of switch battery packs 21 may be connected in parallel to form a switch battery group 21a ' to 21z ', and then the plurality of switch battery groups 21a ' to 21z ' are connected in parallel between the sub-buses 251a-251z, for example, the switch battery group 21a ' is electrically connected between the sub-buses 251a and 251B. Since all of the exchange battery groups 21a 'to 21z' are connected in series, the dc power converter 211 of the exchange battery group 21 must be controlled to ensure that the steady-state total current of each of the exchange battery groups 21a 'to 21z' is the same. In addition, in the present circuit architecture, the number of power conversion units 231a through 231z in operation may be increased or decreased according to the load of the system, so as to maintain the minimum number of power conversion units 231a through 231z in operation, thereby increasing the efficiency of the system. The number of the respective switch battery groups 21a 'to 21z' of each sub-bus 251a to 251z is not necessarily the same. And each exchange battery pack 21 has an independent direct current power converter 211, so the exchange battery pack 21 can be added or withdrawn at any time in the power dispatching task, and the limit that the exchange battery pack 21 can only withdraw but not be added in the power dispatching task is more advantageous than the limit of the battery unit used by the existing battery energy storage power station.

The number of power conversion units 231a through 231z can be increased or decreased with the load to obtain the maximum conversion efficiency, and the dc bus 25 can be flexibly assigned to connect a large number of the switch battery groups 21a 'through 21z'. It should be noted that the above-mentioned groups 21a 'to 21z' are used for convenience of description, and the individual groups 21 may be directly controlled or operated without any group concept, and the groups 21 of the whole groups 21a 'to 21z' must perform the same operation (e.g. charging or discharging).

In addition, as shown in fig. 5A and fig. 5B, the high-power dispatching station needs to be connected with a higher voltage of the power grid 30, and a transformer 26 needs to be connected in series between the higher voltage of the power grid 30 and the ac/dc power conversion device 23 for voltage matching. As shown in fig. 5A, the ac/dc power conversion device 23 may be directly connected in series with the corresponding transformers 261a-261z by the power conversion units 231a-231z, respectively. Alternatively, as shown in fig. 5B, the power conversion units 231a through 231z are connected in parallel to an ac bus 27, and the ac bus 27 is connected to the power grid 30 through a transformer 26.

The existing battery energy storage power plant architecture is that a plurality of batteries are connected in series with a direct current bus, the direct current bus is essentially the same as a battery string and is a standard voltage source, and the direct current bus voltage is the voltage of the battery string and is not needed and cannot be controlled.

The power dispatching system 20 is configured such that a plurality of exchange battery packs 21 are connected to a dc bus 25, the exchange battery packs 21 are a plurality of battery cells 212 electrically connected to each other and are coupled to a dc power converter 211, the dc bus 25 is essentially a dc power converter 211 in parallel in terms of circuitry, the dc power converter 211 of each exchange battery pack 21 must be controlled by an energy control center 24 to ensure the stability of parallel operation and to maintain the voltage of the dc bus 25 (including sub-buses) within a predetermined range. In other words, the energy control center 24 controls the dc bus 25 voltage within a predetermined range by controlling the ac/dc power conversion device 23 and the dc power converter 211 of the exchange battery pack 21, which is one of the technical features of the present invention.

Referring to fig. 3, the energy control center 24 can further assign (or control) the exchange battery pack 21 at least partially located in the accommodating space 22 to participate in a first power dispatching task according to a first power demand command I01, so that the exchange battery pack 21 provides power to the power grid 30 or consumes power of the power grid through the dc bus 25 and the ac/dc power conversion device 23. One energy control center 24 may communicate with one power dispatching station or with a plurality of power dispatching stations at the same time to achieve better dispatching capability.

Here, the so-called first power demand command I01 may be generated by the energy control center 24 in response to the real-time power load condition. The energy control center 24 may schedule the power of the power dispatching station according to the first power demand command I01, so as to be connected to the power grid 30 for generating power or consume the power of the power grid 30.

The electric power dispatching station plays three roles of electric vehicle 100 battery exchange, peak and valley elimination of the power grid 30 and battery energy storage and power generation, for example, holidays mainly use electric vehicle 100 battery exchange (namely, more electric vehicles 100 travel on the road, the electric power dispatching station needs to store more exchange battery packs 21 for replacing the electric vehicles 100, the peak demand of the power grid 30 for example is greatly reduced and the supply and demand are matched), for example, holidays mainly use electric grid 30 peak and valley elimination and battery energy storage and power generation (namely, more electric vehicles 100 are in a static state or in a short-range movement, and therefore most of exchange battery packs 21 are concentrated in the electric power dispatching station). The exchange battery pack 21 for battery exchange of the electric vehicle 100 is mainly charged fully, but the exchange battery pack 21 for peak load elimination of the electric network 30 and battery energy storage and power generation is not necessarily charged fully. The battery exchange function can only be performed by the power dispatching station, so the battery exchange function is generally higher in the power dispatching station.

The spare capacity is the capacity that the power dispatching station reserves for power generation, and is the maximum capacity for power generation after deducting the number of battery exchanges and the capacity thereof, which are expected to be used as the battery exchanges, in relation to the total capacity of all the exchange battery packs 21 stored in the power dispatching station. In a general case, the backup capacity is larger than the maximum capacity at which power generation is possible.

The switching battery pack 21 concentrated in the power dispatching station may be in three states, namely, a charge-in state, a discharge-in state, and a wait-in state. If the state is fully charged, the state can be used as battery exchange or power generation, and if the state is not fully charged, the state can be used as power generation preparation, or after being fully charged, the state can be used as battery exchange or power generation.

The battery capacity of the existing battery energy storage power plant is fixed, namely the standby capacity is fixed. Since the number of the exchange battery packs 21 stored in the power dispatching station varies in response to the demands of the electric vehicles, the load capacity in the power dispatching station varies, which is one of the technical features of the present invention.

The power scheduling method according to the preferred embodiment of the present invention is described below by way of example. First, referring to fig. 6, a flowchart of the concentration of the exchange battery pack 21 to the power dispatching station is shown, which includes steps S01 to S04.

Step S01 is to drive the electric vehicle 100 loaded with the exchange battery pack 21 to the power dispatching station.

Step S02 is to unload the exchange battery pack 21 on the electric vehicle 100 at the power dispatching station. The electric vehicle 100 may be driven to a particular area or space and the exchange battery pack 21 may be unloaded from the electric vehicle 100 by a robotic arm (robotic arm) or other automated device. The robot may be a four-axis or six-axis robot, and is not limited thereto. In addition, the robot arm can assist in completing the unloading work of the exchange battery pack 21 with manpower.

Step S03 is to place the unloaded exchange battery pack 21 into a corresponding exchange battery pack accommodating space in the power dispatching station to prepare for the subsequent charging of the exchange battery pack 21. The unloaded exchange battery pack 21 may be moved to the corresponding accommodating space 22 by an automated guided vehicle (Automatic Guided Vehicle, AGV) or a conveyor, and placed in the accommodating space 22 to connect the corresponding connector. The locked exchange battery pack 21 is unlocked, wherein the unlocking is to enable the bidirectional direct current power converter 211 in the exchange battery pack 21 to charge the battery, so that the battery can be charged. Power is transferred to the switching battery pack 21 through the dc bus 25 to charge it.

Step S04 is to load the charged exchange battery pack 21 to another electric vehicle 100. When another electric vehicle 100 arrives at the power dispatching station and the battery pack 21 needs to be exchanged, the battery pack 21 to be locked is locked, and then the fully charged battery pack 21 can be loaded on the electric vehicle 100 with the need by a mechanical arm or other automation equipment.

Through the above steps, the exchange battery pack 21 can be moved by the electric vehicle 100 between different power dispatching stations and the electric vehicle 100, and the power dispatching stations can be used as the centralized storage points, and naturally, there are also retired exchange battery packs 21 which are not moved. It should be noted that, since the exchange battery pack 21 has the advantages of shape compatibility, the same connector, the same control firmware, etc., the retired exchange battery pack 21 can be directly used in the power dispatching station, which directly improves the value of the retired exchange battery pack 21, and is a ring of the invention for reducing the cost. The same external shape and connection interface are used for the exchange battery pack 21, and the internal battery unit 212 and the dc power converter 211 can increase the capacity of the battery unit 212 or the efficiency of the dc power converter 211 with the progress of technology, and the exchange battery pack 21 can maintain sharing performance but can increase performance with the progress of technology. The same exchange battery pack accommodating space 12 can be used continuously, so that the exchange battery pack 21 in use shares the same exchange battery pack accommodating space 12 with the retired exchange battery pack 21, which is one of the technical features of the present invention. It should be noted that the definition of "retired exchange battery pack 21" is generally defined in the electric vehicle 100 industry as a decrease in actual capacity to 80% of the nominal capacity, i.e., retirement of the battery.

Referring to fig. 7, a flow chart of a power scheduling method is shown. When the utility company finds that the power supply and demand are unbalanced, the utility company can generate power demand instructions according to the real-time power condition to seek assistance from the power dispatching system, which can include the following steps.

In step S11, at a first time, the energy control center 24 receives a first power demand command I01, and starts to execute a first power scheduling task accordingly.

Step S12 is to determine the standby capacity, charging and chargeable capacity of the power dispatching station by the energy control center 24. Here, the energy control center 24 may communicate with the exchange battery pack 21 disposed in the accommodating space 22 to obtain parameter information of the exchange battery pack 21, and perform the optimization operation after obtaining all the information. Wherein the parameter information includes, but is not limited to, the real-time total power of the exchanged battery pack 21.

Step S13 is to assign, by the energy control center 24, at least part of the switching battery packs 21 in the power dispatching stations to participate in the first power dispatching task. In a general operation mode, the power dispatching station can reserve a part of the exchange battery pack 21 according to the battery exchange history as the exchange battery pack for the electric vehicle 100 to be used, and the exchange battery pack 21 with too low power or the exchange battery pack with a larger standby capacity than the power dispatching task is also provided, so that only a part of the exchange battery pack 231 can participate in the first power dispatching task, and such a planning can also be included in the optimization operation described above.

It is further noted that, assuming that the first power demand command I01 represents that the power grid 30 needs 100KW of power, the energy control center 24 may perform the power generation power dispatching task at least in the following manner after obtaining the power capacity information of the power dispatching station. The first way is to supply 100KW of power to the grid 30 by means of the ac/dc power conversion device 23 by discharging the assigned exchange battery pack 21. The second way is to reduce the charging of 100KW by the assigned exchange battery 21, to increase the power grid 30 by 100KW, or both methods are used together to provide the power required by the grid 30.

In addition, regarding the assignment of the switching battery pack 21 to participate in the power scheduling task, "assignment" may be performed in a different manner in addition to the direct assignment described above. Taking a power generation power dispatching task as an example, for example, the accommodating space 22 is divided into a plurality of areas, then the exchange battery pack 21 is placed in the accommodating space 22 of each corresponding area according to the assigned content, and finally the areas are used for alternately generating power by controlling power according to the instruction. In addition, in addition to the power generation by turns in the respective areas, the exchange battery packs 21 in the accommodation space 22 in a certain area may be further assigned to perform power generation by turns in a pre-specified order with control power.

Step S14 is to end the first power scheduling task. When the task is scheduled for generating power, after the task demand is relieved, the power scheduling system 20 may enter a peak elimination mode of the power grid 30, and continue to assist in stabilizing the power grid 30.

In step S15, a second power demand command is received by the energy control center 24 at a second time, and a second power scheduling task is started accordingly. Step S16 is similar to step S12 in that the energy control center 24 determines the capacity of the power dispatching station for standby, charging and recharging. Step S17 is similar to step S13 in that the energy control center 24 assigns at least part of the switching battery packs 21 in the power dispatching stations to participate in the second power dispatching task.

Step S18 is similar to step S14, and the second power scheduling task is ended.

Here, the exchange battery pack 21 in the power dispatching station may be circulated between the electric vehicle 100 and other power dispatching stations, and thus the exchange battery pack 21 may be different with reference to the first power dispatching task and the second power dispatching task. Here, "different" means that the number of the exchange battery packs 21 participating in the power dispatching task is different, the position of the storage space 22 is different, or the main body of the exchange battery packs 21 is different, for example, the battery cells 212 of the different exchange battery packs 21 have different voltages, or the different exchange battery packs 21 have different output currents.

It should be noted that, when the power grid 30 temporarily increases demand in performing the power dispatching task, the power dispatching station may instruct the other exchange battery pack 21 to participate in the power dispatching task halfway during the power generation process. Since each of the switching battery packs 21 has the dc power converter 211 therein, the switching battery pack 21 can directly exit or participate in the power scheduling task during the power scheduling task. In other words, the number of switching battery packs 21 participating in the power scheduling task may be increased or decreased in the course of the power scheduling task. However, in the existing battery energy storage power generation, the battery units are directly connected with the direct current bus, so that a new battery unit cannot be added in the power generation process because the new battery unit is different from the direct current bus in voltage. Therefore, in the process of power dispatching task, when the power demand of the power grid 30 increases or the power demand time is prolonged, the number of the exchange battery packs 21 for grid-connected power generation can be increased timely to support the change of the power grid 30 demand, which is one of the technical features of the present invention.

From the perspective of the exchange battery pack 21, it is one of the main technical features of the present invention that one exchange battery pack 21 performs different power dispatching tasks at different power dispatching stations. Since the exchange battery packs 21 in the power dispatching station accommodation space 22 are all electrically connected to the dc bus 25, during the power dispatching process in the same power dispatching station, part of the exchange battery packs 21 can be charged while part of the exchange battery packs 21 are discharged through the dc bus 25. Meanwhile, if the number of the exchange battery packs 21 used for exchange of the electric vehicle 100 is insufficient, the exchange battery packs 21 in power generation can also be charged by the direct current bus 25. In this way, the amount of power of the exchange battery pack 21 concentrated in the power dispatching station can be optimally controlled to cope with the demand for battery exchange from the electric vehicle 100, which may suddenly increase.

For example, each power dispatching station prepares a sufficient number of fully charged exchange battery packs 21 for battery exchange according to the history, monitors highway traffic information at the same time, and when the exchange battery packs 21 for exchange are insufficient, can charge the exchange battery packs 21 with higher electric power for exchange. Even when the power dispatching station performs the power generation task, the battery charging operation can be performed at any time, and the number of the exchange battery packs 21 for exchange can be increased flexibly.

Further, since the exchange battery pack 21 is connected to the power grid 30 through the dc bus 25 and the ac/dc power conversion device 23, the power grid 30 controls the power dispatching station to perform power utilization or grid-connected power generation through the energy control center 24 for the exchange battery pack 21, and thus efficient power dispatching can be performed by the power dispatching system 20 of the present invention.

In summary, in the power dispatching system and the dispatching method thereof according to the present invention, after the exchange battery packs 21 for the electric vehicles 100 are concentrated, the exchange battery packs 21 for the electric vehicles 100 are adaptively dispatched for use, so as to effectively integrate the increasingly used exchange battery packs 21 for the electric vehicles 100. Further, the exchange battery pack 21 can rapidly provide grid-connected power generation when the power grid 30 needs backup power. In addition, under the condition that the power dispatching system 20 disclosed by the invention is matched with the exchange battery pack 21 with the direct-current power supply converter 211, the quantity of the exchange battery packs 21 can be adaptively dispatched according to the change of the power load, and the quantity of the exchange battery packs 21 can be timely increased or reduced in the grid-connected power generation process. Accordingly, the power demand on the electric grid 30 and the need for the electric vehicle 100 to replace the exchange battery pack 21 will provide the most appropriate dispatch operation, and the charging demand of the electric vehicle 100 is changed from the burden of the electric grid 30 to the helper of the electric grid 30.

The foregoing description is only of the preferred embodiments of the invention and is not intended to limit the scope of the invention. It is intended that all such equivalent modifications and variations as would be within the spirit of the invention be included within the scope of the following claims.

Claims

1. The utility model provides a power dispatching method, is applied to a power dispatching station, and this power dispatching station has a plurality of accommodation spaces, a direct current bus and an alternating current-direct current power conversion equipment, and each accommodation space is provided with a corresponding connector, and these connectors still connect in parallel to this direct current bus, and this alternating current-direct current power conversion equipment couples between this direct current bus and a electric wire netting, characterized by, includes:

a plurality of exchange battery packs detached from different electric vehicles are stored in a centralized manner in the corresponding accommodating spaces, the corresponding connectors of the accommodating spaces are also electrically connected with the exchange battery packs, and each exchange battery pack is provided with a direct current power converter and a plurality of battery units which are electrically connected with each other; and

an energy control center controls the AC/DC power supply conversion device and the exchange battery packs positioned in the accommodating spaces, and the exchange battery packs positioned at least in part in the accommodating spaces are assigned to participate in a first power dispatching task according to a first power demand instruction, wherein the first power dispatching task comprises discharging the DC bus to enable the exchange battery packs to provide power for the power grid through the DC bus and the AC/DC power supply conversion device, and battery units of the exchange battery packs participating in the first power dispatching task have different voltages;

Wherein at least one of the assigned switching battery packs was charged at another power dispatching station.

2. The power scheduling method of claim 1, wherein during execution of the first power scheduling task, the portion of the switched battery pack not participating in the first power scheduling task is charged through the dc bus.

3. The power scheduling method of claim 1, wherein the energy control center further executes a second power scheduling task according to a second power demand command, and assigns a different number of switching battery packs than the first power scheduling task to participate in the second power scheduling task, or assigns a part of switching battery packs not participating in the first power scheduling task to participate in the second power scheduling task.

4. The power dispatching method of claim 1, wherein the energy control center further executes a second power dispatching task according to a second power demand command, wherein at least part of the exchange battery packs participating in the first power dispatching task and the second power dispatching task are located in different accommodating spaces.

5. The power scheduling method of claim 1, wherein the number of switching battery packs participating in the first power scheduling task is increased during the first power scheduling task.

6. The power scheduling method of claim 1, wherein the first power scheduling task comprises a first power scheduling task and a first power scheduling task.

7. The power scheduling method of claim 6, wherein the first power scheduling task is to increase the sum of currents flowing from the switching battery pack to the dc bus.

8. The power dispatching method of claim 6, wherein the first power dispatching task is to increase the sum of currents flowing through the direct current bus to the switching battery pack.

9. The power dispatching method of claim 1, wherein the energy control center controls the voltage of the direct current bus within a preset range.

10. The power scheduling method of claim 1, wherein the partially exchanged battery pack participating in the first power scheduling task also participates in a power scheduling task of another power scheduling station.

11. A power dispatching system for use with a power dispatching station having a plurality of exchange battery packs collectively stored therein from different types of electric vehicles, wherein each exchange battery pack has a dc power converter and a plurality of battery cells electrically connected to each other, at least some of the exchange battery packs having the same shape and different capacity specifications, comprising:

The plurality of accommodating spaces are provided with a corresponding connector for being connected with a corresponding exchange battery pack, and the connectors are also connected to a direct current bus in parallel;

an AC/DC power conversion device coupled between the DC bus and a power grid; and

the energy control center controls the AC/DC power supply conversion device and the exchange battery packs positioned in the accommodating spaces, and assigns at least part of the exchange battery packs positioned in the accommodating spaces to participate in a first power scheduling task according to a first power demand instruction, wherein the first power scheduling task comprises discharging the DC bus, so that the exchange battery packs provide power for the power grid through the DC bus and the AC/DC power supply conversion device;

wherein the battery cells of the exchange battery pack participating in the first power dispatching task have different voltages;

12. The power dispatching system of claim 11, wherein the portion of the switched battery pack not participating in the first power dispatching task is charged via a dc bus during execution of the first power dispatching task.

13. The power dispatching system of claim 11, wherein the switching battery packs participating in the first power dispatching task have different capacity specifications.

14. The power dispatching system of claim 11, wherein the dc power converters in the switching battery pack are non-isolated.

15. The power dispatching system of claim 11, wherein the voltage of the dc bus is higher than the voltage of the battery cells of the switching battery pack.

16. The power dispatching system of claim 11, wherein the ac-dc power conversion device comprises a plurality of power conversion units selected from the group consisting of a dc-to-ac conversion unit, an ac-to-dc conversion unit, and combinations thereof.

17. The power dispatching system of claim 11, wherein the dc power converter in the switching battery is a bi-directional dc power converter.

18. The power dispatching system of claim 11, wherein the ac-dc power conversion device is connected to the power grid through a transformer.